New refresh method callable from the automate

[Ladas]

New refresh method callable from the automate, it tries
to call targeted manager refresh if defined, otherwise fallback to
full refresh.

This is needed for invoking https://github.com/ManageIQ/manageiq-automation_engine/blob/master/lib/miq_automation_engine/engine/miq_ae_engine/miq_ae_builtin_method.rb#L101

[miq-bot]

Checked commit Ladas@f483bb5 with ruby 2.2.6, rubocop 0.47.1, and haml-lint 0.20.0
0 files checked, 0 offenses detected
Everything looks fine. 🍪

[Ladas]

@cc @gmcculloug @blomquisg we need this so we can invoke the new targeted refresh from the automate

the usage is just "/System/event_handlers/refresh" and the targets are scanned inside, or the result can be full refresh, if we disable the targeted refresh via settings.

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@gmcculloug not related CI error it seems?

[gmcculloug]

@lfu Please review

[lfu]

@Ladas Does this refresh method work only for Amazon? Or eventually it will work for all providers?
Would like to know if this is a replacement for event_action_refresh and event_action_refresh_sync.

[Ladas]

@lfu we will use it for targeted refresh of AWS and OpenStack, for 4.6. In other providers, it would just invoke full refresh, because of a missing Settings value.

At some point, it will replace event_action_refresh, but that will take some time. (we will need targeted graph refresh in all providers)

[lfu]

Changes LGTM 👍